Anticipating one's future self is a unique human capacity that contributes importantly to adaptation and health throughout adulthood and old age. Using the adult lifespan sample of the national German Socio-Economic Panel (SOEP; N > 10,000, age range 18-96 years), we investigated age-differential stability, correlates, and outcomes of accuracy in anticipation of future life satisfaction across six subsequent 5-year time intervals. As expected, we observed few age differences in current life satisfaction, but stronger age differences in future expectations: Younger adults anticipated improved future life satisfaction, overestimating their actual life satisfaction 5 years later. By contrast, older adults were more pessimistic about the future, generally underestimating their actual life satisfaction after 5 years. Such age differences persisted above and beyond the effects of self-rated health and income. Survival analyses revealed that in later adulthood, underestimating one's life satisfaction 5 years later was related to lower hazard ratios for disability (n = 735 became disabled) and mortality (n = 879 died) across 10 or more years, even after controlling for age, sex, education, income, and self-rated health. Findings suggest that older adults are more likely to underestimate their life satisfaction in the future, and that such underestimation was associated with positive health outcomes.